Blank for expansible envelope



FIG. 1 is a top plan view of a blank for an expansible envelope embodying my new design, the bottom plan view being the same in appearance;

FIG. 2 is a front elevational edge view of my new design;

FIG. 3 is a side elevational view of my new design, the opposite side elevational view being the same in appearance; and,

FIG. 4 is a rear elevational view of my new design.

The blank is of conventional thickness. The dash lines represent fold lines within the blank structure. 

The ornamental design for a blank for an expansible envelope, substantially as shown and described. 